Enemy of God (Warlord Chronicles Series #2) by Bernard Cornwell

Since the first volume in his magnificent Warlord Chronicles, The Winter King, now the basis for the British TV show, Bernard Cornwell established himself as the storyteller who could reinvent the legend of King Arthur for our time.

In Enemy of God, Cornwell's magical re-creation continues. Having defeated the last holdouts of civil war in southern Britain, Arthur has secured Mordred's throne. But he must still face raging conflicts between the old ways and the new, as well as foes more powerful and more dangerous—because they pose as friends.

Brilliantly written and peopled with the familiar faces of legend along with new ones, Enemy of God is an immensely powerful continuation of a modern classic.